Air-filter.



MIN DELIN MGGERRY.

' AIR FILTER.

APPLICATION FILED FEB.3, 1908.

93 1,014. Patented Aug. 10, 1909.

"UNITED STATES PATENT oinnon.

MIND-ELIN MCGERRY, OF'G'RAND RAPIDS, MICHIGAN, ASSIGNOR TO BERT MCDONALD, OF

' CHICAGO, ILLINOIS.

AIR-FILTER.

Specification o! Izeitters Patent.

' I'a'bn'ted'Aug. 10, 1909.

' Application filed February a, 1903. Serial No. 415027.

ence being had to the accompanying drawings, forming a part thereof.

The purpose of thisinvention is to provide an improved device tobe interposed in any ventilating apparatus for clearing the air by filtering process, taking out the dust and deleterious impurities. which adhere thereto.

It is particularly designed for use in railway cars in connection with a forced circulation of air.

It consists of the features of construction shown and described as indicated in the claims. 1

In the drawin s:Figure 1 is a vertical longitudinal section of a device embodying this invention. Fig. 2 is a section at the line 22 on Fig. 1. Fig. 3 is an end elevation of the device.

In the drawings, A represents a pipe in an air-circulating system, in which, by any means, as an exhaust or blast fan not shown, a forced circulation of air is maintained in the direction of the arrows. Interposed in said pipe is an enlarged chamber, B, constituting part of the conduit. Within this chamber and constituting a transverse obstruction across the entire air path through the chamber is a filtering device which consists of a comparatively thin layer of fiber, C, retained between two sheets of open-meshed wire fabric, D, D, said fabric and the contained layer of fabric being folded into zig-zag form, as seen in Fig. 1, at sharp angles so as to present a very large area of said filtering element within the bounds of the limited cross-sectional area of the chamber, said exposed area of the zig-zag filtering element being many times the area of the cross section of the chamber. In practice, I employ preferably vegetable fiber, such as hemp,

ax .or sisal, but the choice of fiber is a matter' of preference and any fairly fine fiber or fibrous material can be employed. Even excelsior or shredded wood fiber can be used." The wire fabric, D, should be of course mesh, from quarter to half-inch apertures being suitable, but this also is a matter of preference, provided only the mesh be fine enough to safely retain the fiber in view of the fineness of. the fiber,'and prevent its siftingout and accumulating outside the retainingfabric and leaving apertures vacant of fiber through the filtering element. -In orderthat the air current may be widely diffused over the filtering element and also so that it may not strike it so forcibly at any oint as to be liable to blow the fiber out an leave holes, and also as a further assistancev to filtering, I employ preferably a tapering conical-or pyramidal screen, F, of comparatively coarse wire cloth and very much finer than the fabric, B, interposed in the tapering entrance portion, B of the chamber, B, between the inlet section of the pipe, A, and the filtering element, CD. In order to prevent the outgoing air current from carrying any fine dust which it might take from the fiber itself, either having previously been deposited or resulting from the wear of the fiber, I interpose between the filtering element, CD, and the outleading pipe section, A, in the opposite tapered end portion, B of the chamber, a similar pyramidal or conical screen, G, which is a finer wire cloth than the screen, F, and which causes the outgoing current to be uniformly and evenly distributed and free from jets or areas of greater intensity than the remainder, as Well as free from dust which it might otherwise carry from the filtering element.

I claim 1. An air filter comprising, in combination with an air conduit, an enlarged chamber therein having its ends tapering for connection with the adjacent elements to the conduit; a transverse barrier across the entire air path of said conduit at its point of greatest enlargement, consisting of a zigzagged layer of fabric and corresponding zig-zagged retaining sheets of meshedv wire fabric, and tapered diaphragms of relatively fine meshed wire fabric interposed in the tapered end portions of the chamber between the inlet and outlet respectively and said zig-zagged filtering barrier.

2. An air filter comprising, in combination with an air conduit, an enlarged chamber therein having its ends tapering for connection with the adjacent elements to the conduit; a transverse barrier across the entire air path of said conduit at its oint of greatest enlargement, consisting o a zigzagged liter of fabricand corresponding zig-zagge retainin sheets of meshed wire fabric, tapered diap ragms of relatively fine meshed wire fabric interposed in the tapered end portions of the chamber between the inlet and outlet respectively and said zig-zagged filtering barrier, said tapered diaphragins at the outlet side being of finer mesh than at the inlet side.

3. An air filter comprising, in combination with an air'eonduit, an enlarged chamber therein; a transverse barrier across the entire path of said conduit'at its oint of greatest enlargement consistmg o a zigzagged layer of fabric and corresponding zig-zagged retaining sheets of meshed wire fabric, and diaphragms of relatively finemeshed wire fabric interposed in the said enlarged chamber between said filtering barrier and the inlet and outlet respectively in a position inclined at an angle of approxi-' M I NDELIN MCGERRY.

Witnesses:

thus. S. BUR'roN, J. S. Anno'r'r. 

